What size wires are generally used for wiring PLCs ?

For eg: if i take cable length of 1.5m what should be the wire size for PLC supply and control inputs, if PLC is of 24V?

 

wire size used for power is typically as indicated by manufacturer. Wire sizing for I/O is typically 16-18ga stranded, and terminated in a terminal strip for transition to field wiring. You can find field devices/comm wiring directly to PLC. In that case, 'it is what it is'

 

Look my PLC Input contains only push buttons , limit switches, scanner signal etc, for which the PLC doesn't consumes much current.So if i use a 18AWG(0.75mm sqr) of 1.5m having 7A ampacity is it ok? or should i have to go for for 20AWG, 22AWG ETC.I have seen that for control signals PLC consumes apprxmtly 3mA or around it, please clear my doubt.....

 

based on loading, your 18ga will be fine. I can't comment on inhouse standards, your local codes, etc.

 

As i have referenced about cables ampacity, i have seen 20AWG cables have 4A ampacity. But our PLC digital inputs consumes typically 3mA, say 15mA peak. So is 20AWG a good option.I know you have already given you opinion, but please consider this too and suggest if i m wrong.